Zika virus (ZIKV) is a mosquito borne flavivirus, which was a neglected tropical pathogen until it emerged and spread across the Pacific Area and the Americas, causing large human outbreaks ...associated with fetal abnormalities and neurological disease in adults. The factors that contributed to the emergence, spread and change in pathogenesis of ZIKV are not understood. We previously reported that ZIKV evades cellular antiviral responses by targeting STAT2 for degradation in human cells. In this study, we demonstrate that Stat2-/- mice are highly susceptible to ZIKV infection, recapitulate virus spread to the central nervous system (CNS), gonads and other visceral organs, and display neurological symptoms. Further, we exploit this model to compare ZIKV pathogenesis caused by a panel of ZIKV strains of a range of spatiotemporal history of isolation and representing African and Asian lineages. We observed that African ZIKV strains induce short episodes of severe neurological symptoms followed by lethality. In comparison, Asian strains manifest prolonged signs of neuronal malfunctions, occasionally causing death of the Stat2-/- mice. African ZIKV strains induced higher levels of inflammatory cytokines and markers associated with cellular infiltration in the infected brain in mice, which may explain exacerbated pathogenesis in comparison to those of the Asian lineage. Interestingly, viral RNA levels in different organs did not correlate with the pathogenicity of the different strains. Taken together, we have established a new murine model that supports ZIKV infection and demonstrate its utility in highlighting intrinsic differences in the inflammatory response induced by different ZIKV strains leading to severity of disease. This study paves the way for the future interrogation of strain-specific changes in the ZIKV genome and their contribution to viral pathogenesis.
Nanocrystalline nickel of different grain sizes (8–28 nm) was produced by electrodeposition using Watt's bath. Saccharine addition to the bath and pulsed current deposition were effective in lowering ...the grain size of the deposits. The grain size and microstrain of deposits was determined by X-ray diffraction analysis. The microhardness of nanocrystalline Ni ranged between 572 and 724 kg/mm
2. The electrochemical behavior of nanocrystalline Ni was evaluated in 1 mol/l H
2SO
4 and compared with that of coarse-grained nickel. All the nickel samples exhibited active–passive potentiodynamic polarization behavior. The zero current potential, passive current density and breakdown potential generally increased with decrease in grain size. The increased passive current density for nanocrystalline nickel confirmed the defective nature of passive film that forms on nanocrystalline nickel. The tendency for localized corrosion was lower in case of nanocrystalline nickel as indicated by increased breakdown potential. Tafel and linear polarization tests revealed that the corrosion rate of freshly exposed surfaces of Ni decreased with grain size, thereby indicating greater hindrance to anodic dissolution in nanocrystalline Ni. The magnitude of compressive microstrain in the Ni deposits increased with decrease in grain size.
Micro-machined Silicon (Si) diaphragm is extensively studied in Fabry Perot Interferometer (FPI) based pressure sensors, but its applications are limited to non-corrosive media due to poor corrosion ...resistance. Metal alloys such as Copper-Beryllium Alloy (CBA), Stainless Steel (SS) and Ni based alloys have comparable mechanical properties and much better corrosion resistance than Si. But their use as diaphragm for FPI based pressure sensor is much under reported. In this paper, design, analysis and fabrication of an FPI based pressure sensor with CBA diaphragm is discussed. Its sensing probe has two parts, a sensing head and a sleeve, welded together. The sensing head is a three-dimensional monolithic component which consists of pressure sensitive diaphragm and a step for FPI cavity. The sleeve guides the optical fiber to a fixed position such that the cleaved end of the fiber forms an FPI with the diaphragm. Both the sensing head and the sleeve are manufactured by Diamond Turning Machining (DTM) process and have CBA as material of construction. This manufacturing process ensures that flatness on interferometric side of the diaphragm and its parallelism with the fiber end are achieved within 2 µm; surface finish (Ra) on same side of the diaphragm is less than 10 nm. The sensor showed sensitivity of more than 1 µm/bar within the measurement range of 0–7 bar. DTM machined sensing probe with all essential FPI features (flatness, surface finish and parallelism) and welded diaphragm in FP pressure sensor are being reported for the first time to the best of our knowledge.
The study addressed a significant gap in the profiling and understanding of the gut microbiota's influence on Malaysian Malay women with gestational diabetes mellitus (GDM). This prospective cohort ...study aimed to explore the intricate relationship between gut microbiota, dietary choices, and lifestyle factors among Malay women, both with and without GDM. The research specifically focused on participants during the second (T0) and third (T1) trimesters of pregnancy in Johor Bahru, Malaysia. In Part 1 of the study, a diverse pool of pregnant women at T0 was categorized into two groups: those diagnosed with GDM and those without GDM, with a total sample size of 105 individuals. The assessments encompassed demographic, clinical, lifestyle, and dietary factors at the T0 and T1 trimesters. Part 2 of the study delved into microbiome analysis, targeting a better understanding of the gut microbiota among the participants. Stool samples were randomly collected from 50% of the individuals in each group (GDM and non-GDM) at T0 and T1. The collected samples underwent processing, and 16s rRNA metagenomic analysis was employed to study the microbial composition. The results suggested an association between elevated body weight and glucose levels, poor sleep quality, lack of physical activity, greater intake of iron and meat, and reduced fruit consumption among women with GDM compared to non-GDM groups. The microbiome analysis revealed changes in microbial composition over time, with reduced diversity observed in the GDM group during the third trimester. The genera Lactiplantibacillus, Parvibacter, Prevotellaceae UCG001, and Vagococcus positively correlated with physical activity levels in GDM women in the second trimester. Similarly, the genus Victivallis exhibited a strong positive correlation with gravida and parity. On the contrary, the genus Bacteroides and Roseburia showed a negative correlation with omega-3 polyunsaturated fatty acids (PUFAs) in women without GDM in the third trimester. The study highlighted the multifaceted nature of GDM, involving a combination of lifestyle factors, dietary choices, and changes in gut microbiota composition. The findings emphasized the importance of considering these interconnected elements in understanding and managing gestational diabetes among Malaysian Malay women. Further exploration is essential to comprehend the mechanisms underlying this relationship and develop targeted interventions for effective GDM management.
Crystallographic orientation and grain size for monocrystalline and polycrystalline materials respectively play a critical role in defining their mechanical behaviour under nanoindentation. To ...understand their effects on mechanical properties, molecular dynamics (MD) simulations help in revealing the underlying physical phenomena governing the nanoindentation behaviour. This paper attempts to comparatively analyse and study the effects of crystallographic orientations of monocrystalline copper {(100), (110) and (111)} and critical grain size of polycrystalline copper on the nanoindentation response using MD simulations. The results obtained for indentation load vs. depth curve, hardness, dislocations, and elastic recovery were analysed for comparison. Cu(111) exhibited an average hardness of 12.62 GPa, which is 18.27% more than that of Cupoly. The pile-ups of 8 Å size were observed in Cupoly; and this was higher than any of copper system studied here. The dislocation extraction algorithm (DXA) analysis revealed that the total dislocations in Cu(111) was 34.23% and 153.8% lower than that of Cu(110) and Cupoly, respectively. Cu(111) comprised of highest Stair-rod dislocation along with LC and Hirth locks. Furthermore, a prismatic loop comprised of sessile dislocations also appeared in Cu(111). The elastic depth recovery rate for Cu(100) was 52.75%, 41.60% and 40.66% higher than that of Cu(110), Cu(111) and Cupoly, respectively. This study revealed that the nanoindentation based mechanical performances of monocrystalline copper systems, specifically Cu(111) were superior to any other copper systems.
•Monocrystalline copper {(100), (110) and (111)} and polycrystalline copper are compared for nanoindentation response.•Comparative analysis of different copper systems to describe the strain hardening during nanoindentation.•Monocrystalline copper with (111) orientation shows a prismatic dislocation loop comprised of sessile dislocations.•Amorphous structures at the grain boundaries of polycrystalline copper hindered the elastic recovery.
In this paper, we discuss the design, fabrication, and testing of an external Fabry-Perot interferometer (EFPI)-based absolute type fiber optic pressure sensor of range 0-50 mbar. The FPI has ...sapphire as the first reflecting surface and stainless steel (SS) sheet (SS316L of thickness 0.18 mm) as the second one. In order to achieve high specular reflectivity, the reflecting surface of sapphire is coated with a broad band thin film coating, while the SS316L sheet is surface finished with the Chemo Mechanical Magneto Rheological finishing process. The parallelism between two reflecting surfaces of FPI and their individual flatness is around <inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula>/15, which was achieved by precision machining and assembly with stretched diaphragm. The SS sheet also works as the deflecting diaphragm of the pressure sensor and causes change in the FPI gap with applied pressure. FPI gap is calculated from the reflected spectrum by an improvised yet simple scheme. In this paper, FPI is an enclosed cell with vacuum inside, which acts as the reference pressure of the sensor. Applied pressure of 0-50 mbar changed the FPI gap by around <inline-formula> <tex-math notation="LaTeX">17~\mu \text{m} </tex-math></inline-formula>. This sensor was tested with white light interferometric technique, and the best finesse obtained was 5.5. The proposed device is an optical analogous of a capacitance-based pressure sensor. To the best of our knowledge, FPI-based absolute pressure sensors of sub-atmospheric range with a metal diaphragm have not been reported anywhere.
The effect of LaCl
3 and CeCl
3 inhibitor additions in 3.5% NaCl solution on the corrosion behaviour of aluminum alloy AA2014 has been investigated. Four different concentrations (250, 500, 750 and ...1000
ppm) of LaCl
3 and CeCl
3 were studied. The polarization resistance increased significantly and the corrosion rate decreased by an order of magnitude with the addition of 1000
ppm of LaCl
3 and CeCl
3, with maximum decrease noticed for CeCl
3. EIS studies showed that there was a significant increase in overall resistance after addition of 1000
ppm LaCl
3 and CeCl
3, when compared to the case without inhibitor. The double layer resistance and film resistance increased after inhibitor addition. Scanning electron microscopy confirmed formation of precipitates of oxide/hydroxide of lanthanum and cerium on cathodic intermetallic sites, which reduced the overall corrosion rate.
In her recent book, Constitutional Statecraft in Asian Courts, Yvonne Tew develops an ambitious argument for empowering Malaysian judges to promote constitutional democracy. Her arguments rely on the ...idea of an unamendable constitutional ‘basic structure’ or ‘meta-Constitution’ expressive of that ideal. I argue that her proposals are normatively inadequate to this task because Tew relies on resources in constitutional theory traceable to the conservative German thinker Carl Schmitt, whose views about constitutional legitimacy and limits to constitutional amendment form part of an authoritarian political logic designed to subvert constitutional democracy that subordinates legality to power politics. I then argue that Tew's proposals, if applied to Malaysia, risk feeding into elements of Schmittian authoritarian logic that plausibly underwrite Malaysia's ethnocratic context, and conjecture (through case-analysis) that authoritarian judges could easily reconfigure her proposals to legitimate ethno-authoritarian rule. Conversely, conscientious judges who defend constitutional democracy would adopt a non-Schmittian approach that emphasises the normative priority of legality as a constraint on political power to counter ethno-authoritarian rule. Consequently, despite Tew's aspiration to equip judges with tools to defend constitutional democracy, the tools she provides threaten to undermine this aspiration such that her proposals may be characterised as a naïve Schmittian misappropriation.
The corrosion inhibition of pure Al due to addition of different concentrations of LaCl
3 and CeCl
3 in 3.5% NaCl solution has been investigated. Polarization resistance studies revealed that LaCl
3 ...additions provided enhanced increase in surface resistance compared to CeCl
3 additions, with maximum increase noted for 1000
ppm addition for both additions. Electrochemical impedance spectroscopy also revealed the improved corrosion resistance with inhibitor addition. The formation of precipitates of oxides/hydroxides of lanthanum and cerium on cathodic intermetallic sites at low inhibitor concentration and the overall surface at high inhibitor concentration was confirmed by scanning electron microscopy. There was a difference in the morphologies of the rare earth oxides/hydroxides precipitated on the surface of pure Al, with CeCl
3 addition resulting in faceted precipitates and LaCl
3 addition in fine globular precipitates.
The effect of an alkaline surface treatment on the electrochemical behavior of CP titanium, Ti–6Al–4V and Ti–13Nb–13Zr has been investigated by potentiodynamic polarization and electrochemical ...impedance spectroscopy (EIS) techniques. Experiments were performed in Hank’s solution as a function of immersion time. The electrochemical behavior of untreated alloys was also studied. Potentiodynamic polarization experiments conducted after 1 and 168
h of immersion in Hank’s solution indicated minimal change in passive current density for the untreated alloys. EIS data obtained after 1, 24, 72 and 168
h for untreated alloys also indicated minimal change in passive film resistance. In the case of surface-treated alloys, EIS revealed the formation of one additional layer on CP Ti and two additional layers on Ti–6Al–4V and Ti–13Nb–13Zr alloys after surface treatment and immersion in Hank’s solution. Some ideas about the nature of these layers have been obtained by fitting the EIS data to equivalent electrical circuit models. The surfaces of the treated Ti-alloys were also characterized using X-ray diffraction and scanning electron microscopy. The first additional layer has been identified as a sodium titanate hydrogel layer and the second layer, as an apatite layer. The apatite nucleation and growth on the surface occurred after immersion in Hank’s solution. Ti–6Al–4V and Ti–13Nb–13Zr alloys exhibited higher apatite film resistance compared to CP Ti.
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